Derm Dx: A growing rash on a man with a history of sun exposure

A 48-year-old man presents with a rash involving his neck and upper chest. He states that the condition was first noted approximately 18 months earlier, and the rash has been spreading gradually. The man is fair-skinned and relates a history of ample sun exposure. The condition is asymptomatic and has not responded to topical steroid therapy. Examination of the affected ...